ArangoDB Module

const arangodb = require('@arangodb')

This module should not be confused with the arangojs JavaScript driver which can be used to access ArangoDB from outside the database. Although the APIs share similarities and the functionality overlaps, the two are not compatible with each other and cannot be used interchangeably.

The db object

arangodb.db

The db object represents the current database and lets you access collections and run queries. For more information see the db object reference.

Examples

const { db } = require('@arangodb');

const thirteen = db._query('RETURN 5 + 8').next();

The aql template tag

arangodb.aql

The aql function is a JavaScript template string handler (or template tag). It can be used to write complex AQL queries as multi-line strings without having to worry about bindVars and the distinction between collections and regular parameters.

To use it just prefix a JavaScript template string (the ones with backticks instead of quotes) with its import name (e.g. aql) and pass in variables like you would with a regular template string. The string will automatically be converted into an object with query and bindVars attributes which you can pass directly to db._query to execute. If you pass in a collection it will be automatically recognized as a collection reference and handled accordingly.

Queries generated using the aql template tag can be used inside other aql template strings, allowing arbitrary nesting. Bind parameters of nested queries will be merged automatically.

To find out more about AQL see the AQL documentation.

Examples


const filterValue = 23;
const mydata = db._collection('mydata');
const result = db._query(aql`
  FOR d IN ${mydata}
  FILTER d.num > ${filterValue}
  RETURN d
`).toArray();

// nested queries

const color = "green";
const filterByColor = aql`FILTER d.color == ${color}'`;
const result2 = db._query(aql`
  FOR d IN ${mydata}
  ${filterByColor}
  RETURN d
`).toArray();

The aql.literal helper

arangodb.aql.literal

The aql.literal helper can be used to mark strings to be inlined into an AQL query when using the aql template tag, rather than being treated as a bind parameter.

Any value passed to aql.literal will be treated as part of the AQL query. To avoid becoming vulnerable to AQL injection attacks you should always prefer nested aql queries if possible.

Examples

const { aql } = require('@arangodb');

const filterGreen = aql.literal('FILTER d.color == "green"');
const result = db._query(aql`
  FOR d IN ${mydata}
  ${filterGreen}
  RETURN d
`).toArray();

The aql.join helper

arangodb.aql.join

The aql.join helper takes an array of queries generated using the aql tag and combines them into a single query. The optional second argument will be used as literal string to combine the queries.

const { aql } = require('@arangodb');

// Basic usage
const parts = [aql`FILTER`, aql`x`, aql`%`, aql`2`];
const joined = aql.join(parts); // aql`FILTER x % 2`

// Merge without the extra space
const parts = [aql`FIL`, aql`TER`];
const joined = aql.join(parts, ''); // aql`FILTER`;

// Real world example: translate keys into document lookups
const users = db._collection("users");
const keys = ["abc123", "def456"];
const docs = keys.map(key => aql`DOCUMENT(${users}, ${key})`);
const aqlArray = aql`[${aql.join(docs, ", ")}]`;
const result = db._query(aql`
  FOR d IN ${aqlArray}
  RETURN d
`).toArray();
// Query:
//   FOR d IN [DOCUMENT(@@value0, @value1), DOCUMENT(@@value0, @value2)]
//   RETURN d
// Bind parameters:
//   @value0: "users"
//   value1: "abc123"
//   value2: "def456"

// Alternative without `aql.join`
const users = db._collection("users");
const keys = ["abc123", "def456"];
const result = db._query(aql`
  FOR key IN ${keys}
  LET d = DOCUMENT(${users}, key)
  RETURN d
`).toArray();
// Query:
//   FOR key IN @value0
//   LET d = DOCUMENT(@@value1, key)
//   RETURN d
// Bind parameters:
//   value0: ["abc123", "def456"]
//   @value1: "users"

The query helper

arangodb.query

In most cases you will likely use the aql template handler to create a query you directly pass to db._query(). To make this even easier ArangoDB provides the query template handler, which behaves exactly like aql but also directly executes the query and returns the result cursor instead of the query object:

const { query } = require('@arangodb');

const filterValue = 23;
const mydata = db._collection('mydata');
const result = query`
  FOR d IN ${mydata}
  FILTER d.num > ${filterValue}
  RETURN d
`.toArray();

// Nesting with `aql` works as expected
const { aql } = require('@arangodb');

const filter = aql`FILTER d.num > ${filterValue}`;
const result2 = query`
  FOR d IN ${mydata}
  ${filter}
  RETURN d
`.toArray();

It is also possible to pass query options to the query helper (introduced in v3.7.0):

const { query } = require('@arangodb');

const mydata = db._collection('mydata');
const result = query( { fullCount: true } )`
  FOR d IN ${mydata}
  LIMIT 1
  RETURN d
`.data;

The errors object

arangodb.errors

This object provides useful objects for each error code ArangoDB might use in ArangoError errors. This is helpful when trying to catch specific errors raised by ArangoDB, e.g. when trying to access a document that does not exist. Each object has a code property corresponding to the errorNum found on ArangoError errors.

For a complete list of the error names and codes you may encounter see the appendix on error codes.

Examples

const errors = require('@arangodb').errors;

try {
  someCollection.document('does-not-exist');
} catch (e) {
  if (e.isArangoError && e.errorNum === errors.ERROR_ARANGO_DOCUMENT_NOT_FOUND.code) {
    throw new Error('Document does not exist');
  }
  throw new Error('Something went wrong');
}

The time function

arangodb.time

This function provides the current time in seconds as a floating point value with microsecond precision.

This function can be used instead of Date.now() when additional precision is needed.

Examples

const time = require('@arangodb').time;

const start = time();
db._query(someVerySlowQuery);
console.log(`Elapsed time: ${time() - start} secs`);
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